ios - AFNetworking 2.0 + UIProgressView 如何正确显示上传 session 的进度
<p><p>我正在使用 AFHTTPSessionManager 子类通过网络服务下载和上传数据。除了上传进度 View 之外，一切似乎都运行良好，我使用的是 UIProgressView+AFNetworking 类别。<br/>
代码是这样设置的:<br/></p>
<pre><code> NSURLSessionTask * task = [ addMediaWithURI:self.filePath success:^(NSURLSessionDataTask *task, BOOL added) {
if (added) {
NSLog(@"Operation succ");
}
weakSelf.progressContainerView.hidden = YES;
} orFailure:^(NSURLSessionDataTask *task, NSError *error) {
weakSelf.progressContainerView.hidden = YES;
}];
self.progressContainerView.hidden = NO;
;
</code></pre>
<p><br/>
该方法直接调用:</p>
<pre><code>session = [self POST:ApiPostURL parameters:parameters constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
name: ParameterMultimedia error:appendError];
} success:^(NSURLSessionDataTask *task, id responseObject) {
NSLog(@"%@", responseObject);
if ( isEqualToString:@"ko"]) {
NSError * error = ;
failure(task, error);
return ;
}
success (task, YES);
} failure:^(NSURLSessionDataTask *task, NSError *error) {
NSLog(@"%@", error);
failure(task, error);
}];
</code></pre>
<p>一旦我附加了进度 View ，如果我 checkin 它的方法，我可以确定它正确地观察了方法中的任务进度:</p>
<pre><code>- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(__unused NSDictionary *)change
context:(void *)context <br>
</code></pre>
<p>问题是 <code>if ( > 0)</code> 总是 false 因为 <code>countOfBytesExpectedToSend</code> 为 0，阅读有关 <code>NSURLSession</code> 的文档苹果表示:<br/></p>
<blockquote>
<p>Discussion The URL loading system can determine the length of the
upload data in three ways:</p>
<p>From the length of the NSData object provided as the upload body. From
the length of the file on disk provided as the upload body of an
upload task (not a download task). From the Content-Length in the
request object, if you explicitly set it</p>
</blockquote>
<p>如果我从请求 header<code>Content-Leght</code> 的请求中打印值，我会得到一个有效值:</p>
<pre><code>"Accept-Language" = "it;q=1, en;q=0.9, fr;q=0.8, de;q=0.7, ja;q=0.6, nl;q=0.5";
"Content-Length" = 232172;
"Content-Type" = "multipart/form-data; boundary=Boundary+357828FACC07BFAC";
"User-Agent" = "XXXXX/1.0 (iPad; iOS 7.1; Scale/1.00)";
</code></pre>
<p>我不明白为什么总是返回等于 0 的值。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>Googleing，githubbing，我找到了答案，本质上这是 NSURLSession 的“功能”，当您使用 uploadstream 创建 session 时，任务会接管您设置的标题。由于在流中没有真正的内容大小，如果我们设置一些东西，任务将重写它。
<br/>
幸运的是 NSURLSession 有两个请求属性 <code>currentRequest</code>(被覆盖的)和 <code>originalRequest</code>。原始请求将继续保留我们的 <code>Content-Length</code>。 <br/>
我对 UIProgressView+AFNetworking 类别做了一些修改，以使其使用设置的内容长度工作，最好再检查一下是否有流。 <br/></p>
<pre><code>- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(__unused NSDictionary *)change
context:(void *)context
{
#if __IPHONE_OS_VERSION_MIN_REQUIRED >= 70000
if (context == AFTaskCountOfBytesSentContext || context == AFTaskCountOfBytesReceivedContext) {
if () {
//upload content length issue
// if ( > 0) {
NSInteger byteToSend = [[ valueForHTTPHeaderField:@"Content-Length"] integerValue];
if (byteToSend){
dispatch_async(dispatch_get_main_queue(), ^{
/ (byteToSend * 1.0f) animated:self.af_uploadProgressAnimated];
// / ( * 1.0f) animated:self.af_uploadProgressAnimated];
});
}
}
if () {
if ( > 0) {
dispatch_async(dispatch_get_main_queue(), ^{
/ ( * 1.0f) animated:self.af_downloadProgressAnimated];
});
}
}
if () {
if ([(NSURLSessionTask *)object state] == NSURLSessionTaskStateCompleted) {
@try {
;
if (context == AFTaskCountOfBytesSentContext) {
;
}
if (context == AFTaskCountOfBytesReceivedContext) {
;
}
}
@catch (NSException * __unused exception) {}
}
}
}
#endif
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - AFNetworking 2.0 + UIProgressView 如何正确显示上传 session 的进度，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/23193983/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/23193983/
</a>
</p>
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